I've really wanted a water based warframe for a long time, and I've finally came up with workable ideas for powers.

1)
Hydralize
Cost 25
Damage 100/200/300/400
Damage type physics

Single target jet of water that would fire from one of Hydrus' hands. The enemy would be ragdolled and launched through the air the same direction of the stream. If the enemy were to die they would melt as their body was tossed.

2)
Slipstream
Cost 50
Duration 10/20/30/40 seconds

Hydrus creates a long slip stream on the ground about 15m long. Any enemies that step onto the slipstream fall over and slide down the slipstream and are launched off the end. This can be used to slide enemies off the map. the powers are the same costs as others.

Hydrus spawns a geyser that floats enemies up into the air for it's duration within it's radius. The geyser can hold 2/3/4/5 enemies at one time.

4)
Whirlpool
Duration 30/40/50/60
Radius 10/10/10/10 m

Spawn a whirlpool around yourself and allies that prevents enemies and bullets from penetrating. The walls are transparent, however, the visibility is greatly distorted and any out going friendly fire is fired out at a random horizontal direction from the whirlpool.

Let me know your thoughts!

EDIT
in response to comments about the ult it wasn't my original idea. My original idea was as follows:

Create a whirlpool that violently spins all enemies who step into it around the radius. When an enemy dies in the whirlpool dropped resources are thrown into the center of the radius. When the whirlpool dies enemies are ragdolled and thrown.

Bullets fired within the whirlpool are cast out as physics impact instead of hitscan, and enemy bullets that enter pass through to the other side, and are also no longer hitscan.

So bullets become physics impact, ignoring armor, but are harder to aim naturally, and it's also protective.

To differentiate from snowglobe, I would suggest players have to crouch to be inside it, make it more a flat cylinder than a shield - this way players can pop in and out of it to take advantage of its abilities or use it as cover.

Love the concept, but bleh...that ult sounds really terrible, no offense to your creativity. Having not only your teammates view skewed but their damage skewed sounds awful. Not to mention it really just sounds like Frost's Snow Globe.

Maybe something more like "Pulls all enemies in a radius towards Hydrus before doing damage and violently flinging them outwards".

it seems like a soul punch of sorts. there are already a bunch of good projectile skills. maybe you could change this into a slash type ability that damages (and maybe ragdolls on death) all enemies in an arc in front of you.

this is a good idea, but change it into a round base so that it makes sense to slip in any direction. not just along your path. also, move this to the third skill (mainly because most movement impairing skills such as snow globe are iirc, third skills.

seems like a watered down (pun intended) version of bastille. if you remove the duration, it seems like a bounce that does damage. you already have slipstream as a crowd control. maybe you could change this into an AoE pushback (no knockdown, but with damage). like a burst of water coming from hydrus. make this the second skill.
i guess you could revolve this frame around the idea of limitless targets (can hit ALL enemies within radius - same with first skill). they deal less damage than conventional frames, but deal that damage to ALL enemies.

this seems like a bigger version of vortex :/ i know its hard to avoid ideas that dont repeat (and some ideas in-game already do). You dont have to necessarily deal damage instantly or render the enemy completely useless for the duration of the skill (see: Molecular prime and rhino stomp). an example of this would be loki's ult. it doesnt deal damage but helps his overall theme.
if you would take my advice and create a frame focused on hitting all enemies, with lesser damage, then the ult COULD be somewhere along the lines of huge resistance reduction. you could say the water rusts the armor, makes them weaker to electricity, more vulnerable to frost, etc..

somewhere along the lines of, "if you get hit by my ult, consider yourself 30 levels weaker in terms of tankiness"

1st power - water projectile that deals serrated blade damage and ranking it up causes it to tear through enemies causing damage to any other enemy in its path

2nd power - causes a blast of water/liquid that jams enemy weapons and dissolves armor. Ranking it up would increase its effectiveness and give a chance to kill lightly armored enemies

3rd power -creates a whirlpool or X radius depending on rank which repels and stagers enemies that attempt to breach it

4th power (ulti) - summons a tornado/hurricane that sucks in enemies within x radius dealing damage over a period of time and hurls enemies away from point of casting. Both radius and damage over time increase with rank.

I had actually thought about this before though didn't really get around posting it. Can't think of a better water based warframe profile. I'd call him Poseidon

Edit: being water based powers, I'd probably add reduced fire and poison damage to allies/caster within range of the abilities

I've always paired Saryn with Ash. Silent stoic type with a sexy teacher-type (maybe I read too much manga). Then we could pair up Nova with Frost with Frost being some sort of calm protector and Nova being a needy little kid (I read too much manga lol).

Anyways, maybe Rhino and Ember? Both are tanky characters (if Ember has Overheat). Maybe Rhino could be a berserker while Ember could be a wild valkyrie or Amazon type?

second ability is too gimmicky and i would never slot it because first ability already does better cc (ragdoll)

third ability, again, has cc.

fourth ability just looks like a copy of frost's bubble with the gimmick of horribly affecting your damage the same way bullet attractor does.

should maybe play more on the role of water in the Warframe universe, though. it seems almost magical and is used to power the orokin ships in particular (that and their literal power plants). so instead of thinking of a slip 'n slide, go for space power voodoo?

Seems REALLY underpowered, but I like the idea of a water-element frame. Something I'd say for a power, maybe the 75E one, would be to create a sphere of water around an enemy that they slowly drown in over time. Any enemies coming within the radius of the affected enemy would also start to drown.

Like others here I like your concept. I like the idea of slipstream, and whirlpool. A few people seem to not like it for being similar to snowglobe, but that's what I like about it, admittedly I think it needs tweaking. Maybe it works like banshees ult and hydrus has to remain in the middle for the duration, during that time any enemies inside are ragdolled out in a random direction, any shots going in get sent out in another direction and any shots out also get sent out in a random direction. It offers complete protection for any tenno on the inside but you can't control where the damage will go. You can protect the pod spinning and throwing incoming damage and enemies away but you couldn't leave the whirlpool or it gets shut down. Watching a heavy Grineer get thrown back into his troops, or the stream of infested flying away in random directions would be hilarious and make people separate it from snowglobe.

I think as water you could have some healing powers for support. At the moment there's trinity, but a frame with support cc and a little offensive would be nice.

My suggestion for hydralize is to be a constant jet of water for 2/3/4/5 seconds, that ragdolls enemies you hit, without causing huge amounts too damage. So you can wash enemies away or pin them against a wall.

For healing, I can't think of much, but maybe spewing a stream of health orbs. So there's a limit to how much you can heal, and other Tenno need to collect them. Maybe they come out the geyser? Or your whirlpool heals tenno that come in? It's like saying your not going to shoot straight but at least when the whirlpool stops your at full health. I don't know but another frame with healing and cc would be nice rather than damage.

Hydralize is a bit too similar to Soul Punch, but I still don't think Nekros should even have Soul Punch and it fits better with this theme. If Nekros lost Soul Punch in favour of something else I'd be fine with Hydralize.

Geyser sounds very comparable to Bastille.

Whirlpool sounds okay, but as others have said obscuring the view of your allies opens up too many options for griefing. Plus, if I'm understanding your description correctly, it'd essentially shut down your gun damage for the duration.

Your original Whirlpool is too similar to Vortex.

But those complaints are ultimately irrelevant. So far DE have done a fantastic job of not putting water in their game - and where they have put it in, it can't be interacted with. With the physics they currently have in-game, I would be very surprised if they were complacent with the idea of water not having a physical presence - but it's an incredibly ambitious task to make water look and feel right, particularly when it's doing things that water doesn't usually do (eg. forming a stand-alone whirlpool around an individual).

Maybe some time in the future - a year or two perhaps - once they've got a water planet in the game and the physics nailed down I could see them doing it, but it just seems like too ambitious of a project for now.